George Lucas planned two direct sequels to the original Star Wars. One of them you've seen—it's called The Empire Strikes Back. The other was a back-up plan in case Episode IV had floundered.

Based on the 1978 book Splinter of the Mind's Eye by Alan Dean Foster, the film would have been rushed as a cheap sequel and seen Luke and Leia on a mission of recruitment for the Rebel Alliance. Why the strange plot line? Foster has stated a few reasons in interviews. For one thing, the fog-shrouded planet of Circarpous IV made for a cheap set piece. The props from the first movie could all be recycled. And Harrison Ford had yet to sign on for a second movie when Foster wrote the book, so he left out Han Solo.

Somewhere there's a parallel universe where this midnight movie came to fruition. Maybe we need to get Disney on the line … though, knowing what we know now, the romantic tension in the novel between Luke and Leia might scare them off.

2 of 6

Star Trek: Planet of the Titans

Star Trek is rife with never-weres and false starts. Just consider the transformation of Phase II, a planned live action series with the original crew, into 1979's Star Trek: The Motion Picture. However, the first plan for a Star Trek movie was the mid-1970s mission to make Planet of the Titans, which would have seen a return of the original crew.

Two concepts were batted around. Philip Kaufman, writer of The Outlaw Josey Wales and later Raiders of the Lost Ark, wanted a story of Spock at odds with a Klingon commander, played by Akira Kurosawa movie mainstay Toshiro Mifune. Chris Bryant and Allan G. Scott's version was … quite different. A search for a missing James T. Kirk would land the Enterprise on an alien world. To stop an insidious plot by the planet's inhabitants, the Enterprise would plunge into a black hole and re-emerge on the other side as the inspiration for the Greek gods.

Of all of the undeveloped Star Trek ideas, this is probably the weirdest. I mean, maybe aside from the idea for an episode that was basically Attack of the 50 Foot Woman. Or the Lwaxana Troi sitcom that might have aired on the Sci-Fi Channel.

3 of 6

The Other Robocop 2 (and yet another one)

The Frank Miller-written Robocop 2 was, shall we say, not terribly well received. But the bomb of movie, directed by Irvin Kirshner, was just one of a handful of possible visions for the follow-up. Miller himself says there were a half-dozen other scripts. Eventually the world saw a comic called Frank Miller's RoboCop based on one of many drafts of the script. Its over-the-top violence and dearth of plot led to mixed or negative reviews.

But before all that mess ever happened, a script by original Robocop scribes Ed Neumeier and Michael Miner was announced for the sequel. Their vision involved RoboCop dying in the beginning, disintegrated into dust. He reconstitutes 25 years later to greet a world that is a mix of the original's dystopian version of Detroit and a hyper-capitalist society somewhere between Idiocracy and an R-rated Wall-E, with mind-numbing television and a society built on sensory overload, robot prostitution, and the need to buy-buy-buy. This treatment never got beyond a rough draft pitched to the studio, who turned it down and sought out Frank Miller instead.

4 of 6

Teenage Mutant Ninja Turtles 4

Teenage Mutant Ninja Turtles III, in which our heroes time-travel back to feudal Japan, was hardly a raging success. So a proposed fourth film would have been a reset of sorts in which the turtles and Master Splinter receive "secondary mutations." Michelangelo became closer to half-human, half-turtle in appearance. Donatello went nearly blind and augmented himself with cybernetic technology to compensate. Leonardo basically became Colossus from X-Men, able to turn his skin into metal. Raphael and Splinter would have taken on more feral appearances, with Raphael becoming essentially a velociraptor with a hardshell. It also featured a fifth turtle—and no, it wasn't Venus de Milo. Instead we got Kirby, named after Marvel legend Jack Kirby.

The sequel would also have introduced multiple parallel dimensions and other odd sci-fi plotting, along with darker overtones. But it failed to launch, and we wouldn't see more TMNT movies until the 2007 animated version and 2014's Michael Bay-driven cow-a-bummer.

5 of 6

Masters of the Universe II

The end of the original Masters of the Universe teased the return of Skeletor. The costumes and set pieces were ready. Everything was in place. But then the notoriously cash-strapped production house Cannon Films ran into a little problem: Their check to Mattel for the licensing rights bounced. Cannon was left ready to go into production on a film, but without the rights to make it. (Fun fact: They had the same problem with the Spider-Man film they wanted to make as a concurrent production.)

Instead, Cannon made Cyborg with Jean Claude Van Damme using the costumes and set pieces for the Masters of the Universe sequel and Spider-Man cheapy. Cyborg currently holds a 14 percent on Rotten Tomatoes, while Masters of the Universe sits at 17 percent. So at least it holds up about as well.

6 of 6

Batman: Year One

If you've ever thought to yourself that Batman movies should be a little more like Pi or Black Swan, then please accept our apologies for the fact that this film was never made.

Before Christopher Nolan was given the reins to reinvent Batman on the big screen, Darren Aronofsky had a rather interesting take on the dark knight for a planned relaunch of the franchise in which Bruce Wayne was not a multi-millionaire but rather an angry, formerly homeless auto mechanic. Alfred was no butler, but the shop's owner. Batman's gadgets were homemade weapons straight out of Ragnar Benson. Oh, and Bruce spends the entire movie obsessively writing letters to his dead father.

Sounds rather bleak, but at least it probably would've been more interesting than Gotham.

A Part of Hearst Digital Media
Popular Mechanics participates in various affiliate marketing programs, which means we may get paid commissions on editorially chosen products purchased through our links to retailer sites.